Strength in the quadriceps muscles improves more (16.5 Nm) in older men with muscle loss who take collagen supplements during strength training than those taking a placebo (7.3 Nm).

Older men with muscle loss who do strength training and take collagen supplements gain more muscle mass (4.2 kg) than those taking a placebo (2.9 kg).

When young men do isometric leg exercises for 12 weeks, their thigh muscles get bigger—and that bigger muscle size helps explain about 1 in 5 of their strength gains, even if their nerves aren’t getting better at telling muscles to work harder.

Strength training boosts bone mass in older men with muscle loss, but adding collagen supplements doesn't make it better than just training alone.

Doing full-body strength training three times a week for three months can boost thigh muscle size by about 10–11% in older adults, even for those over 85 — showing that very old age doesn’t stop muscles from growing with exercise.

Older men with muscle loss who take collagen supplements during strength training lose more body fat (5.4 kg) than those taking a placebo (3.5 kg).